Different containers have existed for many years and are used for a variety of products.
Methods of administering metered doses from a dosing device are known, however, most are directed to dispensing liquid forms, such as creams, lotions, and fluids.
Plungers with an internal chamber and springs have been used as metering devices.
Prior art foam metering devices have been described as inaccurate and imprecise and can be complex and expensive.
Methods and apparatuses for dispensing content from single and from multiple containers are known in the art. They can involve the use of complex and sophisticated devices that can add significantly to the cost of the intended product. Such disclosures also do not address the problems of dispensing a predetermined amount of content in a relatively simple and seepage free way from a container.
Methods for the volumetrically controlled dosing of foams have been described using a metering valve in which valve inlet and outlet passages control the flow of a fluid into a limited reservoir or confined space of a specific measure within the internal valve structure or within a narrow delivery passage known as a metering or dosing chamber. Such devices provide a limited chamber and are only capable of containing very small and fixed aliquots of material. Such devices can also be susceptible to undesirable dripping, seepage and the like through the discharge passage or past the operating parts. These metering valves also involve a relatively large number of components which have to be constructed with a high degree of accuracy. These metering valves can add substantially to the cost of the product and do not permit or facilitate quick and economic filling of the pressurized containers through the metering valves with the material which is later to be metered therefrom.
Some prior art foam metering devices use an external reservoir that first has to be filled and emptied, which is separate from the canister valve and from the actuator apparatus. Such devices require a special valve or a continuous valve and cannot be used with canisters with standard valves. Also the devices require a special elastic membrane or diaphragm. In some prior art metering devices a dispensing member moves within the reservoir.
Where the metering mechanism is provided within the internal valve structure, prevention of seepage or and leaking, which is so critical with regard to the internal valve, becomes more difficult as a more complex structure must be provided. Complexity leads to increased risk of malfunction. Also, malfunction of an internal valve structure requires discarding of the entire can together with unused aerosol formulation.
In some prior art devices, such as with metering aerosol buttons or actuator caps, if insufficient depressing force is applied, the discharge passage is not fully closed but the internal valve within the aerosol device is nevertheless “cracked” or partially opened, whereby a continuous flow of aerosol substance occurs, defeating the metering action. Thus, a disadvantage of these metering aerosol buttons or actuator caps is that a non-metered or continuous discharge can occur if inapplicable pressure is applied to the actuator button, which pressure is insufficient, for example, to fully shift all of the operative, relatively movable parts to the loading or filling position. A further disadvantage is that release only occurs whilst the actuator button is fully or almost fully depressed and removal of pressure may result in an incomplete dose.
In some prior art metering aerosol buttons or actuator caps, the exit of fluid is prevented by the depressive force of on operator pressing down on a diaphragm.
Some prior art metering valves can prevent fast filling of the containers since the filling substance must pass around the metering passages in the metering valve.
Methods of mixing doses from dual chamber devices are known, however, many are directed to mixing of doses prior to their expansion and release as a foam, for example where the doses are contained and mixed in narrow constraints and remain in a liquid phase.